Lubricating oil additive



l atented July 19, ,1 949 corporation of Ohio No firawing.

, pplication May 29, 1946,

Serial No. 673,153

2 Glaiiiisa (Cl. 252 50) In accordance with the ihventien. it has teen found that an unsaturated tertiary aliphatic amine in which one of the aliphatic radicals is relatively long, i. e., contains at least 10 and generally not over 24carbon atofns, and the other two radi ears are i iatively i. a, contain from 1 it s carton atam's, massive; are particularly advaii tageeus armament additives for lubricants. A small amount of such an additive incorporated in amt-mating grease imparts thereto a that improvement in its sludge, viscosity iiicrease; lacquer; and acid number characteristics.

Commercial octadecenylamine may be com-era ed to corresponding dialkyl tertiary amine by heating with a lower alkyl chloride, e. g., methyl chloride. The reaction mass is treated with caustic and the tertiary amine recovered. It may be "washed with water to remove inorganic salts, if desired. In view er its ready availability this amine will be used for illustrative purposes.

The airiih used in atirdance with the invention should contain at least one olefinic double bond in the molecule, preferably the long chain. Typical unsaturated tertiary amines are: octadecenyl-dimethylamine, hexadecenyl dimethyl'- amine, tetradecenyl-dimethylamine, dodecenyldimethylamihe, deceiiyl-dimethylamine, and the corresponding tertiary amines wherein either one or both of the methyl groups are replaced by ethyl, propyl, butyl or pentyl radicals, or the corresponding dienyl or trienyl amines. Analogous polyamines which contain no amine hydrogen, i. e., no hydrogen attached directly to a nitrogen are also suitable.

The amount of the additive to be incorporated in an oil or grease will depend on the characteristics of the base oil or grease and the intended 2 i use. Some 011s have were at a tendency to -ions acids, sludges and lacquer deposits than-others, and such oils requlfe larger quantities or use additive agent. In general, for lubricating oils the range is from 1 to 10% by weight but under some circumstances amounts as low as .01% show a significant improvement; For certain special uses the amount may be as high as 25.0% by- Weight. 0f course, it will be uneconomical to add more of the additive than is necessary to impart the desired properties to the lubricant.-

In order to demonstrate the properties of the unsaturated tertiary amines containing one long aliphatic chain as additives for lubricating oils, a number of amines were incorporated into a cornventional lubricating 611. The lubricating oils containing these amines were tested according to laboratory test procedures for evaluating the s w ab i p ls cri e i sp r by R. E; Burk, E. 0. Hughes, W. E. ScoVill and J. D. Bartleson presented t the Atlantic cits meeting of the American Chemical society in September 1941,- and in another paper by the same authors presented at the New Yorl; city meeting of the American Chemical society in September 1944, published in Industrial and Enineering Chemistry, Analytical Edition, vol; 17, No; 5, May 1945, pages 302-309. The latter paper also correlates the results of such laboratory tests-Withthe so-called standardized Chevrolet Engine Test. V

Essentially thelaboratory test equipment consists of a vertical thermostatically heated, large glass test tube, into which is placed a piece of steel tubing-0f about one-third its length and of much smaller diameter; A piece of cppper-lead bearing strip is suspended within and from the upper end of the steel tube by a copper pin,- and an air inlet is provided for admitting air into the lower end of the steel tube in such a way that in rising the air will causethe oil present to circulate, The test tube is filled with an amount of the oil to be tested which is at least sufiicient to submergethe metals;

The ratios of surface active metals to the volume of oil in an internal combustion test engine are nearly quantitatively duplicated in the test equipment. In the Standard test the temperature used is approximately the average tempera- 60 ture of the crankcase. The rate of air flow per volume of oil is adjusted to the same as the average for a test engine in operation. or the catalytic eflfects, those due to iron are the most important. They are empirically duplicated by the addition of a soluble iron salt. Those due to leadbromide are duplicated by its addition. In the Standard test, 0.012% of iron salt is added; and in the Iron Tolerance test this is increased to 0.05%. The duration of the test is adjusted to that usually used in engine type tests. The Iron Tolerance tests were run at 280 F. for thirty-six hours. I

As is showntb'y the data in the paper referred to, the laboratory tests have been correlated with engine tests and the properties of the oil in an engine may be determined from the result of the laboratory tests.

The results given in the following table were obtained from tests using:

A 160 cubic centimeter sample of the lubricant composition 70 liters of air per hour 100 square centimeters of steel. surface 4.4 square centimeters of copper-lead surface 1.0 square centimeters of copper surface 0.01% by weight of lead bromide powder 0.05% soluble iron calculated as F6203 (Ferric Z-ethylhexoate in GP. benzene) 3 of octadecenyl-dimethylamine. The results are as follows:

Concentration of additive in per cent by weight None 3 Lacquer (Inga). 21. 9 l. 6 Sludge mgs 532 20.3 Acid No 6. 6 l. 2 Viscosity increas 635 61 The unsaturated tertiary amine improves every indicated characteristic of the oil.

Iron Tolerance tests on a conventional Mid- Continent acid-treated lubricating oil base stock (-SAE 30) containing different amine compositions were run. The results given in the following table are representative.

The amine compositions used for comparative purposes are: Example 1.Composition comprising primarily octadecenyl-dimethylamine (unsaturated tertiary) Example 2. Composition comprising primarily octadecylamine (primary saturated) Example 3.Composition comprising primarily octadecenylamine and octadecadienylamine (primary unsaturated) Example 4.--Composition comprising primarily dioetadecylamine (secondary saturated) Emample 5.Composition comprising primarily cetyl dimethylamine (tertiary saturated) The amounts of these amines used in the tests are calculated to give approximately equal nitrogen concentrations.

It will be evident from this data that the unsaturated tertiary amine of Example 1 is markedly superior to the saturated primary amine of Example 2, the. primary unsaturatedamine of Example -3, the saturated secondary amine of Example 4, or the saturated tertiary amine of Example 5. A comparison of Examples 1 and 3 shows the efiect of replacing the two hydrogens to form an unsaturated tertiary amine, and a comparison of Examples 1 and 4 shows the improvement attributable to the double bond, i. e., decreased sludge, lower acid number (indicating less corrosion), and lower viscosity increase, thereby indicating improved antioxidant effects for the unsaturated tertiary amine. The additives will find particular use in specialty oils, such as turbine, instrument, anti-rust oils, etc.

The expression deteriorative lubricant refers to any oils and greases which are subject to oxidation, especially these from petroleum sources.

The invention broadly contemplates all Variations and modifications which will be apparent to one skilled in the art in view Of the foregoing disclosures, except as do not come Within the scope of the appended claims.

I claim:

1. A lubricant consisting essentially of a. mineral lubricating oil and an amount to inhibit oxidation of said oil of an oxidation inhibiting amine having the formula wherein R is an aliphatic hydrocarbon radical of 10 to 24 carbon atoms and having one double bond, and R1 and R2 are alkyl radicals having one to five carbon atoms.

2. A lubricant comprising a mineral lubricatlng oil and an amount to inhibit oxidation of said oil of an oxidation inhibiting amine having the formula where R is an aliphatic hydrocarbon radical of 18 carbon atoms and having one double bond, and R1 and R2 are methyl groups.

JOHN. D. BARTLESON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,888,023 Adams Nov. 15, 1932 2,110,199 Carothers Mar. 8, 1938 2,268,608 McNulty et a1 Jan; 6, 1942 

